I’ve been reminded by Chris Aldrich of something I think I knew before:

[M]ost major CMSes (including Known) strip out or severely limit (for security reasons) the html that is accepted in comment fields. … Many also will mark as spam comments that have one or more URLs in them. As a result doing fancy or even mildly complicated html or markdown in replies is something for which most platforms just don’t build.

That’s fair enough. As ever, spammers are spoiling things for everyone. I do have an objection, though. If I am legitimately signed into my own site which, in the #indieweb, is where I will be if replying to some other site, then I’m unlikely to inject malicious code. And if I’m a spammer, and signed in under a false flag, then I’m not likely to need such subterfuges.

A really helpful CMS would, surely, allow me to do all the formatting I want on something I am generating myself, regardless of the specific type of entry.

Chris makes another point:

The other issue in status updates and replies is that they’re often syndicated to other platforms and it’s a more difficult issue to properly do this with each snowflake social media silo depending on how they individually handle html/markdown (or not).

Well, yes. But that’s not my problem on my site. Let them strip all they want, frankly, as long as the leave the link to my reply alone. As Chris acknowledges …

Either way, the end result on the other person’s site isn’t something I can ever control for, so I try not to sweat it too much. :)

For now, I think I’ll sweat this just a little, and add the u-in-reply-to by hand, and hope that does the needful.